A site with good info on using Mason jars for canning, storage and other uses Via: 31 Ways to Use a Mason Jar in Your Kitchen - Keeper of the Home
We use them as drinking glasses in addition to food storage. And for crafting(I use them for making my candles/soaps).
Used them as a post hole bank... put your money in one and place it in a post hole add some dirt and the post... string your wire and no one knows where it is except you...
I never knew you could buy these. I like this. Also, like @VHestin we use ours for drinking glass,plus I store lots in them. When I go to the co-op and buy small amounts, I use mason jars to store my purchases.
Around here the.. I don't know what to call them, let's call them drunken car enthusiasts who listens to 50ies music and grease their hair. Anyways they use those jars for drinks when they are in the cars not to spill anything on the seats.
I would say the Mr uses them to store his Apple Pie Shine in, but store isn't the right word. Around here Mason jars are the flyover states on the coast to coast flight between the still and his stomach. I used them to make some cute snow globes last Christmas. Also the lids on the Parmesan cheese shakers will screw onto them so I used a few of those to put my crushed red chili peppers in, to shake over pizza and whatnot.